Optical lighting instrument

ABSTRACT

An instrument for and a method of producing a series of images of symbols on a photosensitive film. A light beam is directed through a symbol carrier and an image of the symbol is optically projected at two different locations in a common plane concurrently. One image is received on a photosensitive material but is initially filtered to avoid producing an image prematurely. The other image is received on a phosphorescent material that retains the image of previously projected symbols for comparison. The images are together adjusted and the image on the photosensitive material is then recorded by removing the filter and increasing the light intensity.

United States Patent [191 3,864,698 Holthusen Feb. 4, 1975 OPTICAL LIGHTING INSTRUMENT Primary Examiner-John M. Horan [75] Inventor: Bemd Holthusen Hamburg Attorney, Agent, or Firm-Watts, Hoffman, Fisher &

Germany Heinke Co.

[73] Assignee: Dr. Boger Photosatz GmbH 57 ABSTRACT [22] Filed: Sept. 14, 1972 1 An instrument for and a method of producing a series [21] Appl' 288946 of images of symbols on a photosensitive film. A light v beam is directed through a symbol carrier and an [52] U.S. Cl. 354/5 image of t sym l is pti ally pr ject d at two dif- [51] Int. Cl 3411) 27/38 ferent locations in a mm n plan n urr ntly. One [58] Field of Search 95/4.5; 354/5 ag s r i d n a ph sensiti material but is initially filtered to avoid producing an image prema- [56] Referen Cit d turely. The other image is received on a phosphoresc- UNITED STATES PATENTS ent material that retains the image of previously projected symbols for comparison. The images are tog i gether adjusted and the image on the photosensitive 3:080:802 3/1963 Friede l:IIIIIIIII: :1: 95/45 material is e by lemming the filter and 3,259,040 7/1966 Kumagai 95/11 mcreasmg the light Intensity- 3,626,830 12/1971 Sobottka 95/45 10 Claims, 5 Drawing Figures PATENTEDFEB 41915 SHEET 2 [IF 2 1 OPTICAL LIGHTING INSTRUMENT BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to an optical lighting instrument, and more particularly to an instrument which can optically image symbols arranged on a movable carrier individually in a plane on both photosensitive and phosphorescent material. The imaging on the phosphorescent material serves to allow the image of a symbol, held by the photosensitive material, to be visible on the phosphorescent material at least until the next symbol is imaged, so that the correct size and arrangement of the symbols can be set by visual viewing. The photosensitive material is subsequently processed and used for printing.

2. Prior Art Optical lighting instruments are known in which symbols, for example letters of the alphabet in a certain style of writing, are arranged on a type carrier and projected by optical means on photosensitive material which is lighted in this way. As the photosensitive material moves along in steps and several letters are projected in succession, the text of a line may be set, for example. The type carrier is generally formed of a film strip on which the letters of the alphabet and possibly figures also are arranged. One difficulty in such lighting instruments is that the next letter to be set must be exactly established in its position in relation to the letters already set. This adjustment takes place, preferably, by moving a table on which the film is arranged.

in carrying out this adjustment, it is known to project an image first on a special paper or a phosphorescent foil, on which the type already set are visible, so that the operator can see at least the last letter set, when the adjustment of the following symbol takes place.

In a known optical lighting instrument working by this process, the film strip to be lighted is in a holder, above which a slide can be swung which bears the phosphorescent foil on its upper side. In the position of the slide above the film, in which the film and the phosphorescent foil lie exactly one above the other, the type just to be set is projected, first with weak light, on the phosphorescent foil and adjusted exactly. Then the phosphorescent foil is lighted briefly with strong light, after which, with lighting switched off, the slide is swung away. The previously set adjustment of the table under the optic is retained and with this adjustment the film is lighted to record an exact image of the type as set. Then the film and the phosphorescent foil are moved parallel to each other and relative to the path of rays of the imaging optic, and the process can be repeated with the next symbol to be set, while at least the pre-set letter and preferably still other pre-set letters are visible on the phosphorescent foil. The operator receives, in this way, a visual impression of the record which has gone before.

A drawback with this known construction is the fact that several work steps in succession are required since, after adjusting, first the phosphorescent foil must be lighted and only after swinging away the slide bearing this can the film be lighted. Thus, there must be lighting three times in succession with different intensities of light. When a large number of symbols, for example in the case of a long text, must be set, there is a considerable expenditure of work and time with this construction. Also, the slide must be guided exactly and the phosphorescent foil must always be brought back into the same original position to avoid errors in the position of the next letter to be set.

SUMMARY OF THE INVENTION The purpose of the invention is to provide an optical lighting instrument of the kind mentioned, with visual control on a phosphorescent luminous foil or film in which, after adjustment of the type to be set, only one work step is necessary for the lighting of both the normal photosensitive material and the luminous foil and which requires no additional moving parts for the movement of the luminous foil in relation to the photosensitive material for its lighting.

This is accomplished in accordance with the present invention by separately focusing two portions of a beam in which a symbol is imaged to two different locations; in particular, by utilizing optical means comprising two objectives, lying in the same plane, designed alike and movable in common in the direction of the optical axis which image the same symbol from the type carrier at two locations opposite each other in a plane not overlapping and of the same size. The photosensitive material is arranged at one of the locations and the phosphorescent material at the other. This arrangement permits the simultaneous lighting of photosensitive material and luminous foil. The lighting of the two materials in succession is thus eliminated so that one step is saved in the setting of each individual letter. The device for the swinging of the luminous foil on the coordinate table of the optical lighting instrument, on which the two materials are arranged, is also eliminated and with this they can be moved in all directions for adjustment.

According to a preferred embodiment, the opening or aperture of the objective lens for imaging onto the phosphorescent material (the so-called control objective) is greater than that of the other or layout objective lens imaging on the photosensitive material. The control objective may be fully opened to advantage and the layout objective restricted, as by a diaphragm. Suitably, the control objective transmits 10 to 20 times and preferably 16 times as much light as the layout objective.

This embodiment is especially advantageous because the photosensitive material requires much less light than the luminous foil. As a result, the aperture of the layout objective lens can be reduced, producing a great depth of sharpness as compared to the fully open control objective. Thus, when the operator produces a sharp, fine image on the luminous foil, which is lighted by the fully opened objective, a sharp image is assured on the photosensitive material.

One embodiment of this invention provides that in the beam of the layout objective a shutter is arranged which is to be opened for a predetermined time for the lighting. The shutter is suitably arranged directly after the layout objective. Preferably it consists of a red filter. By the arrangement of the shutter, it is possible to control the lighting of the photosensitive material, not only by the aperture opening controlled by the diaphragm, but also by a predetermined lighting time. The design of the shutter as a red filter has the advantage that the actual symbol to be recorded is visible to the operator during the adjustment on the photosensitive material, which is essentially insensitive to red light of the intensity used.

Another embodiment of the invention is constructed so that the light intensity of the lamp to be used for the lighting is adjustable between a setting intensity in which no visible traces are left behind on the'phosphorescent material and a much stronger lighting intensity which, with its action during a predetermined time, brings out an easily visible phosphorescence. The shutter is suitably opened only during a fraction of the predetermined time.

A preferred practical embodiment of the invention provides that the plane of the type carrier is vertical and arranged substantially perpendicular to and at the height of the line of vision of the operating person and that a roof-edge prism deflects the light rays coming from the type carrier downward by 90 to the objective lenses, arranged with vertical optical axes. Based on this arrangement, the operator can view the letters or other symbols to be set on the type carrier by looking straight at the correct or front side and by a glance downward can also see the symbol just projected, also correctly imaged, because the roof-edge prism not only deflects the beam downward by 90, but at the same time reverses the image so that the right-side image is projected. This arrangement is especially advantageous because the operator can now judge, for example, which of several similar but differently designed letters best fit with letters previously set.

An especially advantageous further feature of the lighting instrument according to the invention, which especially facilitates use in daylight, is the provision of a light-proof box, which box is connected by means of a light-proof bellows to the optical system above it and has a viewing shaft, provided with a viewing slit, blackened on the inside and extending diagonally upwards toward the operator, through which the two image locations in the viewing plane are visible. A red filter is arranged to block. thepath of any light beam traveling from the viewing slit to the photosensitive material.

The red filter is preferably near the viewing slit. This design makes it possible to carry out the lighting not, as up to now, in dark rooms, but rather in normal daylight.

In one advantageous construction of the invention, the plane containing the type carrier is arranged vertically and substantially perpendicular to as well as clearly below the line of vision of the operator and the light rays coming from the type carrier are directed, without deflection, on the objectives which are arranged with horizontal optical axes. To make working in daylight possible with this design, a lightproof box is arranged over the photosensitive and phosphorescent materials which lie in a vertical viewing plane, which box is connected through a light-proof bellows to the optical system located before it, and has a viewing shaft provided with a viewing slit blackened on the inside and extending diagonally upwards toward the operator through which image locations in the viewing plane are visible. A red filter, which suitably lies near the viewing slit, is located in the path of the direct light rays from the viewing slit to the photosensitive material. This embodiment is distinguished by a very compact construction, requiring little space.

The phosphorescent material is preferably placed on an endless strip, guided around two turning rolls arranged in the light-proof box, of such length that the phosphorescence is completely extinct after one revolution. The design of the phosphorescent material as an it from behind outside the optical path of the imaging rays so that all the type can be seen and judged by the operator during the operation of the instrument.

According to another embodiment of the invention, a light box is arranged in front of the objective plane of the type carrier containing a lamp and condensor. A transparent window lighted by the lamp and including operating instructions is provided on the side of the box toward the operator. The lamp is used, therefore, not only for the lighting of the photosensitive and phosphorescent materials, but to make visible the operating instructions arranged on the window.

Thecarrying along of film and phosphorescent strip preferably takes place at the same time by turning a single knob. In this way, not only is operation made easier, but an excellent precision of setting is assured.

One embodiment is distinguishedby the fact that the light-proof box, together with all the parts enclosed in it, is adjustable in a horizontalplane perpendicular to the viewing direction of film and phosphorescent strip. ln this way, the height adjustmentof the letters on the photosensitive material may be made.

In another embodiment in which optical axes of the objectives run horizontally, the holder of the type carrier is adjustable in the vertical direction so as to be able to adjust the arrangement of the symbols in height on the photosensitive material.

The above and other features of this invention will become better understood from the detailed description that follows, which is to be considered in connection with the accompanying drawings.

BRIEF'DESCRlPTlON OF THE DRAWINGS FIG. 1 is a schematic perspective broken view of a first form of execution of the lighting instrument according to the invention; and,

FIG. 2 is a schematic perspective broken view of a second simplified form of execution of the lighting instrument according to the invention.

' DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1, an instrument embodying the present invention is shown having a type carrier 11, which contains the letters of the alphabet, figures and punctuation symbols on a strip of film. The type carrier is so placed on the front side of a holding device or support 28 extending transversely to the instrument that the row of letters to be set is visible upright and rightside for the viewer. The type carrier 11 is lighted from behind by means of an elongatedlight source 41 placed in the holder 28 so that the symbols are easily visible.

A type character of the carrier 11 is lighted to form an image in the usual way by means of a lamp 29 and a condenser 30. The imaging takes place, according to sensitive material 24 on the one hand, and on the other on a phosphorescent material 25. The objectives 12, 13 are fastened to a slide, adjustable in common, so that their movement takes place together.

The phosphorescent material is placed on an endless strip guided around turning rolls 26, while the photosensitive material 24 is on a film, which is carried between two cassettes 27.

According to the invention, the control objective 12, forming an image on the phosphorescent material, is fully opened, i.e. has a large aperture, while the identically formed layout objective 13 is substantially stopped down to a small aperture. A diaphragm 23 produces, for example, an opening ratio of 1 to 22 (effective lens diameter to focal length), while the control objective 12' may'have an opening ratio of l to 5.6.

A shutter 14 is supported behind the layout objective 13 in the path of the light transmitted. The shutter is movable into and out of the path by a solenoid 38 and is in the form of a light filter such as a red filter that only transmits light rays of a color to which the photosensitive material is essentially insensitive. The solenoid 38 is provided with an exciting voltage through lines 15.

The phosphorescent and the light sensitive materials 25 and 24 respectively are enclosed in a lightfast box 16 shown in phantom, which has an opening, enclosed by a bellows 17, through which the imaging of the objectives 12, 13 takes place. The lightproof box 16 also has a viewing shaft 19 diagonally forward and upward with a viewing slit 18 through which the operator has a clear view of the photosensitivematerial 24 and the phosphorescent material 25. In the direct path of the rays from the viewing slit 18 to the photosensitive material 24, is interposed a red filter 20, which prevents an undesired lighting of the material 24 from outside, but does not obstruct the imaging path of rays from the objective 13.

The height of the parts supporting the type carrier 11 is so chosen that they are substantially at the height of the axis 21 of the eye 39 of the operator. The whole lighting and type carrying part is supported for height adjustment by a stand 33, so that by movement above or below the height of the eye 39, different image sizes can be obtained. Sharp setting takes place by focusing movement in common of the objectives 12, 13 in the direction of their optical axes.

The entire lighting assembly is enclosed in a box 31, on the back side of which a window 32 is provided, which consists, for example, of transparent material and is uniformly lighted from within the box by the lamp 29 through another condensor 40. In this way, operating instructions for the instrument are made easily visible on the window 32 to the operator.

The phosphorescent band 25 and the film 24 can be moved along rigidly coupled mechanically through a drive mechanism (not shown) operated from a control knob 34. To facilitate an easy threading of the photosensitive material 24 to the cassette 27, an advancing mechanism is provided in front of the windup cassette 27 which consists of a drive roll operable by means of a rotatable knob 43 and located below the photosensi tive material, a drive roll (not shown) arranged above the latter, and pressure plates operable by means of a push button 42. By simultaneously pressing the button 42 and turning the knob 43, the material can be fed toward the cassette 27 until a pair of main drive rolls takes over the advancement of the photosensitive material.

To be able to carry out the height adjustment of the letters on the photosensitive material 24, the whole arrangement, with the lightproof box 16, the photosensitive and phosphorescent materials 24 and 25 respectively can be moved in a horizontal plane, perpendicular to the direction of movement of the endless strip, by means of a rotatable knob 36. Through a knob 37, the lighting and type-carrying part in its entirety can be adjusted in height, by which different degrees of enlargement are possible.

While in the embodiment of FIG. 1 the lighting part is arranged with a horizontal and the imaging part with a substantially vertical optical axis, the embodiment of FIG. 2 locates the optical axes of all the optical elements substantially horizontally in which case, however, the symbols on the type bearer are positioned upside down in a holder 35. The same reference figures with a prime designation apply to similar or corresponding parts in FIGS. 2 and in FIG. 1.

The design of the lighting instrument according to FIG. 2 is essentially the same as that shown in FIG. 1, but the adjustment of the letters on the photosensitive material in the vertical direction is done by moving the type carrier holder 35 in the direction of the double arrow in FIG. 2. The box 16 is moved forward and back by means of a rotatable knob 44.

The setting of the correct size of letter takes place by operating a knob 37 by means of which distance of the type carrier from the objectives l2, 12 can be varied. The sharp setting takes place againby common axial movement of the objectives 12', 12. v

The two forms of execution described operate as follows:

First the red filter shutter 14 is placed in the path of the rays, and the lamp 29, with brightness reduced through a control circuit, is turned on. In the form of execution according to FIG. I, a red-light lamp 4], behind the type carrier, is also turned on to make all the letters of the type carrier visible. Now the desired letter is moved into the optical plane of the imaging beam of the lamp 25.

The letter appears now, both on the photosensitive and on the phosphorescent materials, 24 and 25, respectively. Because of the imaging through the red filter shutter 14 and the viewing through the viewing slit 18, the operator sees the letter on the photosensitive material red, and on the phosphorescent material 25, white, since the rays there are not interrupted by any red filter. Now the approximate correct height position of the letter on the photosensitive material can be set by operating the knob 36 or by moving the holder 35.

The light intensity of the lamp 29, restricted or reduced at this stage, is not sufficient to bring out a marked phosphorescence (after-glow) in the phorphorescent material 25. The letter projected can be seen on the material 25, however.

After adjustment of the image, the lamp 29, through a time switch (not shown), is operated at a greater intensity, i.e., full lighting power for a predetermined time, while the red filter shutter 14 is opened through a time switch for a predetermined time also. In this way, on the one hand the desired lighting of the photosensitive material 24 is effected, and on the other hand,

an after-glow of the phosphorescent material 25 is brought out. The two time switches may be so coupled that they are actuated by operating a common lever. After the photosensitive and the phosphorescent materials, 24 and 25 respectively, are lighted with very different light intensities, the lamp 29 switches back automatically to the reduced intensity and the red filter shutter 14 is automatically closed again. Then, by means of the setting knob 34, the photosensitive and the phosphorescent materials 24 and 25 are moved along, while at the same time, the next letter to be set, after being brought into the plane of the objectives, is imaged by the reduced light intensity. Since the previous letter is still visible on the luminous strip, the correct spacing of the next letter no longer presents any difficulties. The process is now continued until the complete line is set.

Instead of the" phosphorescent foil with long afterglow duration, there may be used according to the invention oscillograph paper lighted by mercury vapor light or pre-activated photo materials, which also, immediately after lighting, gives a visible image of the type imaged.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example, and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

What is claimed is:

1. In an optical lighting instrument for composing symbols on a photosensitive material, which includes a light source, a photosensitive material and a phosphorescent material in coplanar adjacent relationship, a symbol carrier, optical means for imaging a symbol movable by the carrier into a focal plane of the optical means individually onto the photosensitive and phosphorescent materials, the imaging onto the phosphorescent material serving to provide a visible image identical to that recorded by the photosensitive material at least until a subsequent symbol is imaged, so that a desired relationship of successive symbols can be set utilizing visual observation, and the symbol carrier and light source on one hand and the optical means on the other hand being relatively movable in the direction of the optical axis of said optical means, the improvement wherein said optical means includes two objective elements movable in common in the direction of the optical axis which image a symbol from the symbol carrier at two adjacent coplanar spaced positions, the imaged symbols being of equal size and non-overlapping, the photosensitive material is located at one of said spaced positions and the phosphorescent material at the other, a shutter is arranged to selectively obstruct rays passing through the objective element that image onto the photosensitive material and is adapted to be opened for a predetermined time for recording an image on the photosensitive material, and wherein means is included to regulate the intensity of the rays that image onto the phosphorescent material between a setting intensity, by which no visible trace is left behind on the phosphorescent material, and a much stronger intensity which by acting for a predetermined time, brings out an easily visible phosphorescence.

2. A lighting instrument according to claim 1, including means for opening said shutter during only part of said predetermined time.

3. In an optical lighting instrument for composing symbols on a photosensitive material, which includes a light source, a photosensitive material and a phosphorescent material in coplanar adjacent relationship, a symbol carrier with symbols on said carrier oriented in a vertical plane that facilitates viewing at eye level in a directionsubstantially perpendicular to said vertical plane, optical means for imaging a symbol movable by the carrier into a focal plane of the optical means individually onto the photosensitive and phosphorescent materials, the imaging onto the phosphorescent material serving to provide a visible image identical to that recorded by the photosensitive material at least until a subsequent symbol is imaged, so that a desired relationship of successive symbols can be set utilizing visual observation, and the symbol carrier and light source on one hand and the optical means on the other hand being relatively movable in the direction of the optical axis of said optical means, the improvement wherein said optical means includes two objective elements arranged with substantially vertical optical axes and movable in common in the direction of the optical axes which image a symbol from' the symbol carrier at two adjacent coplanar spaced positions, and further including a prism that deflects a beam of light coming from the symbol carrier by to the objective elements, the imaged symbols being of equal size and nonoverlapping, wherein the photosensitive material is located at one of said spaced positions and the phosphorescent material at the other, and wherein a lightproof box encloses the photosensitive and phosphorescent materials, which lie in a horizontal viewing plane,

, which box is connected through a bellows lightfast with the optical means, and has a viewing shaft provided with a viewing slit blackened on the inside and directed diagonally upwards from said viewingplane, through which both materials are visible, and a red light filter in the path of the direct beam of light from the viewing slit to the photosensitive material.

4. A lighting instrument according to claim 3, wherein the red filter is located adjacent the viewing slit.

5. A lighting instrument according to claim 3, wherein the phosphorescent material is carried on an endless strip around two turning rolls within the lightproof box, and is of such length that a phosphorescent image is fully extinguished after one revolution.

6. A lighting instrument according to claim 3, wherein the photosensitive material is arranged on a film movable between two lightproof cassettes located outside the lightproof box.

7. ln an optical lighting instrument for composing symbols on a photosensitive material, which includes a light source, a photosensitive material and a phosphorescent material in coplanar adjacent relationship, a symbol carrier, optical means for imaging a symbol movable by the carrier into a focal plane of the optical means individually onto the photosensitive and phosphorescent materials, the imaging onto the phosphorescent material serving to provide a visible image identical to that recorded by the photosensitive material at least until a subsequent symbol is imaged, so that a desired relationship of successive symbols can be set utilizing visual observation, and the symbol carrier and light source on one hand and the optical means on the other hand being relatively movable in the direction of the optical axis of said optical means, the improvement wherein said optical means includes two objective elements movable in common in the direction of the optical axis which image symbol from the symbol carrier at two adjacent coplanar spaced positions, the imaged symbols being of equal size and non-overlapping, the photosensitive material is located at one of said spaced positions and the phosphorescent material at the other, the symbols on said carrier are oriented in a vertical plane substantially perpendicular to the optical axis of said optical means and at a level approximately the same as that of said material, wherein rays of light coming from the symbol carrier are directed without deflection to the objective elements which are arranged with substantially horizontal axes, wherein the photosensitive and phosphorescent materials lie in a vertical viewing plane, and the instrument further includes a lightproof box over the photosensitive and phosphorescent materials, a lightproof bellows extending from said box toward said optical means, a viewing shaft to said box provided with a viewing slit, blackened inside, and directed diagonally upward from said viewing plane and through which both materials are visible, and a red light filter in the path of the direct rays of light from the viewing slit toward the photosensitive material.

8. A lighting instrument according to claim 7, wherein the phosphorescent material is carried on an endless strip around two turning rolls within the lightproof box, and is of such length that a phosphorescent image is fully extinguished after one revolution.

9. A lighting instrument according to claim 7,

wherein the photosensitive material is arranged on a film movable between two lightproof cassettes located outside the lightproof box.

10. In an optical lighting instrument for composing symbols on a photosensitive material, which includes a light source, optical means for imaging a symbol movable by a carrier into a focal plane of the optical means individually onto photosensitive and phosphorescent materials, the imaging onto the phosphorescent material serving to provide a visible image identical to that recorded by the photosensitive material at least until a subsequent-symbol is imaged, so that a desired relationship of successive symbols can be set utilizing visual observation, and the symbol carrier and light source on one hand and the optical means on the other hand being relatively movable in the direction of the optical axis of said optical means, the improvement wherein said optical means includes two objective elements movable in common in the direction of the optical axis which image a symbol from the symbol carrier at two spaced positions, the imaged symbols being of equal size and non-overlapping, the photosensitive material is located at one of said spaced positions and the phosphorescent material at the other, the phosphorescent material is carried on an endless strip around two turning rolls, the photosensitive material is arranged on a film movable between two light proof cassettes, and a single rotatable knob provides concurrent movement of both.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 33 4 93 Dated February 4, 1975 Inventor(s) Bernd Holthusen It is certified that error appears in the above-identified patent I v and that said Letters Patent are hereby corrected as shown below:v

Column 6, line 31,. delete "12", second occurrence, and

insert 13' v Column 6, line 33, delete "12", second occurrence, and

' insert l3 Column 9, line 3 (claim 7) after "image" insert a Signed and sealed this 17th day of June 1975.

(SEAL) Arte-st:

C. IIARSI-IALL DANN RUTH C. PLATE-OI? Commissioner of Patents Arresting Officer and Trademarks 

1. In an optical lighting instrument for composing symbols on a photosensitive material, which includes a light source, a photosensitive material and a phosphorescent material in coplanar adjacent relationship, a symbol carrier, optical means for imaging a symbol movable by the carrier into a focal plane of the optical means individually onto the photosensitive and phosphorescent materials, the imaging onto the phosphorescent material serving to provide a visible image identical to that recorded by the photosensitive material at least until a subsequent symbol is imaged, so that a desired relationship of successive symbols can be set utilizing visual observation, and the symbol cArrier and light source on one hand and the optical means on the other hand being relatively movable in the direction of the optical axis of said optical means, the improvement wherein said optical means includes two objective elements movable in common in the direction of the optical axis which image a symbol from the symbol carrier at two adjacent coplanar spaced positions, the imaged symbols being of equal size and nonoverlapping, the photosensitive material is located at one of said spaced positions and the phosphorescent material at the other, a shutter is arranged to selectively obstruct rays passing through the objective element that image onto the photosensitive material and is adapted to be opened for a predetermined time for recording an image on the photosensitive material, and wherein means is included to regulate the intensity of the rays that image onto the phosphorescent material between a setting intensity, by which no visible trace is left behind on the phosphorescent material, and a much stronger intensity which by acting for a predetermined time, brings out an easily visible phosphorescence.
 2. A lighting instrument according to claim 1, including means for opening said shutter during only part of said predetermined time.
 3. In an optical lighting instrument for composing symbols on a photosensitive material, which includes a light source, a photosensitive material and a phosphorescent material in coplanar adjacent relationship, a symbol carrier with symbols on said carrier oriented in a vertical plane that facilitates viewing at eye level in a direction substantially perpendicular to said vertical plane, optical means for imaging a symbol movable by the carrier into a focal plane of the optical means individually onto the photosensitive and phosphorescent materials, the imaging onto the phosphorescent material serving to provide a visible image identical to that recorded by the photosensitive material at least until a subsequent symbol is imaged, so that a desired relationship of successive symbols can be set utilizing visual observation, and the symbol carrier and light source on one hand and the optical means on the other hand being relatively movable in the direction of the optical axis of said optical means, the improvement wherein said optical means includes two objective elements arranged with substantially vertical optical axes and movable in common in the direction of the optical axes which image a symbol from the symbol carrier at two adjacent coplanar spaced positions, and further including a prism that deflects a beam of light coming from the symbol carrier by 90*, to the objective elements, the imaged symbols being of equal size and non-overlapping, wherein the photosensitive material is located at one of said spaced positions and the phosphorescent material at the other, and wherein a lightproof box encloses the photosensitive and phosphorescent materials, which lie in a horizontal viewing plane, which box is connected through a bellows lightfast with the optical means, and has a viewing shaft provided with a viewing slit blackened on the inside and directed diagonally upwards from said viewing plane, through which both materials are visible, and a red light filter in the path of the direct beam of light from the viewing slit to the photosensitive material.
 4. A lighting instrument according to claim 3, wherein the red filter is located adjacent the viewing slit.
 5. A lighting instrument according to claim 3, wherein the phosphorescent material is carried on an endless strip around two turning rolls within the lightproof box, and is of such length that a phosphorescent image is fully extinguished after one revolution.
 6. A lighting instrument according to claim 3, wherein the photosensitive material is arranged on a film movable between two lightproof cassettes located outside the lightproof box.
 7. In an optical lighting instrument for composing symbols on a photosensitive material, which includes a Light source, a photosensitive material and a phosphorescent material in coplanar adjacent relationship, a symbol carrier, optical means for imaging a symbol movable by the carrier into a focal plane of the optical means individually onto the photosensitive and phosphorescent materials, the imaging onto the phosphorescent material serving to provide a visible image identical to that recorded by the photosensitive material at least until a subsequent symbol is imaged, so that a desired relationship of successive symbols can be set utilizing visual observation, and the symbol carrier and light source on one hand and the optical means on the other hand being relatively movable in the direction of the optical axis of said optical means, the improvement wherein said optical means includes two objective elements movable in common in the direction of the optical axis which image symbol from the symbol carrier at two adjacent coplanar spaced positions, the imaged symbols being of equal size and non-overlapping, the photosensitive material is located at one of said spaced positions and the phosphorescent material at the other, the symbols on said carrier are oriented in a vertical plane substantially perpendicular to the optical axis of said optical means and at a level approximately the same as that of said material, wherein rays of light coming from the symbol carrier are directed without deflection to the objective elements which are arranged with substantially horizontal axes, wherein the photosensitive and phosphorescent materials lie in a vertical viewing plane, and the instrument further includes a lightproof box over the photosensitive and phosphorescent materials, a lightproof bellows extending from said box toward said optical means, a viewing shaft to said box provided with a viewing slit, blackened inside, and directed diagonally upward from said viewing plane and through which both materials are visible, and a red light filter in the path of the direct rays of light from the viewing slit toward the photosensitive material.
 8. A lighting instrument according to claim 7, wherein the phosphorescent material is carried on an endless strip around two turning rolls within the lightproof box, and is of such length that a phosphorescent image is fully extinguished after one revolution.
 9. A lighting instrument according to claim 7, wherein the photosensitive material is arranged on a film movable between two lightproof cassettes located outside the lightproof box.
 10. In an optical lighting instrument for composing symbols on a photosensitive material, which includes a light source, optical means for imaging a symbol movable by a carrier into a focal plane of the optical means individually onto photosensitive and phosphorescent materials, the imaging onto the phosphorescent material serving to provide a visible image identical to that recorded by the photosensitive material at least until a subsequent-symbol is imaged, so that a desired relationship of successive symbols can be set utilizing visual observation, and the symbol carrier and light source on one hand and the optical means on the other hand being relatively movable in the direction of the optical axis of said optical means, the improvement wherein said optical means includes two objective elements movable in common in the direction of the optical axis which image a symbol from the symbol carrier at two spaced positions, the imaged symbols being of equal size and non-overlapping, the photosensitive material is located at one of said spaced positions and the phosphorescent material at the other, the phosphorescent material is carried on an endless strip around two turning rolls, the photosensitive material is arranged on a film movable between two light proof cassettes, and a single rotatable knob provides concurrent movement of both. 